Re-order the last ChangeLog entry
[glibc.git] / nscd / initgrcache.c
blob255b121ddcc28cb7a13a39e6aa62e4e36d1c4b38
1 /* Cache handling for host lookup.
2 Copyright (C) 2004-2006, 2008, 2009, 2011, 2012 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@redhat.com>, 2004.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published
8 by the Free Software Foundation; version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, see <http://www.gnu.org/licenses/>. */
19 #include <assert.h>
20 #include <errno.h>
21 #include <grp.h>
22 #include <libintl.h>
23 #include <string.h>
24 #include <time.h>
25 #include <unistd.h>
26 #include <sys/mman.h>
28 #include "dbg_log.h"
29 #include "nscd.h"
30 #ifdef HAVE_SENDFILE
31 # include <kernel-features.h>
32 #endif
34 #include "../nss/nsswitch.h"
37 /* Type of the lookup function. */
38 typedef enum nss_status (*initgroups_dyn_function) (const char *, gid_t,
39 long int *, long int *,
40 gid_t **, long int, int *);
43 static const initgr_response_header notfound =
45 .version = NSCD_VERSION,
46 .found = 0,
47 .ngrps = 0
51 #include "../grp/compat-initgroups.c"
54 static time_t
55 addinitgroupsX (struct database_dyn *db, int fd, request_header *req,
56 void *key, uid_t uid, struct hashentry *const he,
57 struct datahead *dh)
59 /* Search for the entry matching the key. Please note that we don't
60 look again in the table whether the dataset is now available. We
61 simply insert it. It does not matter if it is in there twice. The
62 pruning function only will look at the timestamp. */
65 /* We allocate all data in one memory block: the iov vector,
66 the response header and the dataset itself. */
67 struct dataset
69 struct datahead head;
70 initgr_response_header resp;
71 char strdata[0];
72 } *dataset = NULL;
74 if (__builtin_expect (debug_level > 0, 0))
76 if (he == NULL)
77 dbg_log (_("Haven't found \"%s\" in group cache!"), (char *) key);
78 else
79 dbg_log (_("Reloading \"%s\" in group cache!"), (char *) key);
82 static service_user *group_database;
83 service_user *nip = NULL;
84 int no_more;
86 if (group_database != NULL)
88 nip = group_database;
89 no_more = 0;
91 else
92 no_more = __nss_database_lookup ("group", NULL,
93 "compat [NOTFOUND=return] files", &nip);
95 /* We always use sysconf even if NGROUPS_MAX is defined. That way, the
96 limit can be raised in the kernel configuration without having to
97 recompile libc. */
98 long int limit = __sysconf (_SC_NGROUPS_MAX);
100 long int size;
101 if (limit > 0)
102 /* We limit the size of the intially allocated array. */
103 size = MIN (limit, 64);
104 else
105 /* No fixed limit on groups. Pick a starting buffer size. */
106 size = 16;
108 long int start = 0;
109 bool all_tryagain = true;
110 bool any_success = false;
112 /* This is temporary memory, we need not (and must not) call
113 mempool_alloc. */
114 // XXX This really should use alloca. need to change the backends.
115 gid_t *groups = (gid_t *) malloc (size * sizeof (gid_t));
116 if (__builtin_expect (groups == NULL, 0))
117 /* No more memory. */
118 goto out;
120 /* Nothing added yet. */
121 while (! no_more)
123 long int prev_start = start;
124 enum nss_status status;
125 initgroups_dyn_function fct;
126 fct = __nss_lookup_function (nip, "initgroups_dyn");
128 if (fct == NULL)
130 status = compat_call (nip, key, -1, &start, &size, &groups,
131 limit, &errno);
133 if (nss_next_action (nip, NSS_STATUS_UNAVAIL) != NSS_ACTION_CONTINUE)
134 break;
136 else
137 status = DL_CALL_FCT (fct, (key, -1, &start, &size, &groups,
138 limit, &errno));
140 /* Remove duplicates. */
141 long int cnt = prev_start;
142 while (cnt < start)
144 long int inner;
145 for (inner = 0; inner < prev_start; ++inner)
146 if (groups[inner] == groups[cnt])
147 break;
149 if (inner < prev_start)
150 groups[cnt] = groups[--start];
151 else
152 ++cnt;
155 if (status != NSS_STATUS_TRYAGAIN)
156 all_tryagain = false;
158 /* This is really only for debugging. */
159 if (NSS_STATUS_TRYAGAIN > status || status > NSS_STATUS_RETURN)
160 __libc_fatal ("illegal status in internal_getgrouplist");
162 any_success |= status == NSS_STATUS_SUCCESS;
164 if (status != NSS_STATUS_SUCCESS
165 && nss_next_action (nip, status) == NSS_ACTION_RETURN)
166 break;
168 if (nip->next == NULL)
169 no_more = -1;
170 else
171 nip = nip->next;
174 ssize_t total;
175 ssize_t written;
176 time_t timeout;
177 out:
178 timeout = MAX_TIMEOUT_VALUE;
179 if (!any_success)
181 /* Nothing found. Create a negative result record. */
182 written = total = sizeof (notfound);
184 if (he != NULL && all_tryagain)
186 /* If we have an old record available but cannot find one now
187 because the service is not available we keep the old record
188 and make sure it does not get removed. */
189 if (reload_count != UINT_MAX && dh->nreloads == reload_count)
190 /* Do not reset the value if we never not reload the record. */
191 dh->nreloads = reload_count - 1;
193 /* Reload with the same time-to-live value. */
194 timeout = dh->timeout = time (NULL) + db->postimeout;
196 else
198 /* We have no data. This means we send the standard reply for this
199 case. */
200 if (fd != -1)
201 written = TEMP_FAILURE_RETRY (send (fd, &notfound, total,
202 MSG_NOSIGNAL));
204 /* If we have a transient error or cannot permanently store
205 the result, so be it. */
206 if (all_tryagain || __builtin_expect (db->negtimeout == 0, 0))
208 /* Mark the old entry as obsolete. */
209 if (dh != NULL)
210 dh->usable = false;
212 else if ((dataset = mempool_alloc (db, (sizeof (struct dataset)
213 + req->key_len), 1)) != NULL)
215 dataset->head.allocsize = sizeof (struct dataset) + req->key_len;
216 dataset->head.recsize = total;
217 dataset->head.notfound = true;
218 dataset->head.nreloads = 0;
219 dataset->head.usable = true;
221 /* Compute the timeout time. */
222 timeout = dataset->head.timeout = time (NULL) + db->negtimeout;
224 /* This is the reply. */
225 memcpy (&dataset->resp, &notfound, total);
227 /* Copy the key data. */
228 char *key_copy = memcpy (dataset->strdata, key, req->key_len);
230 /* If necessary, we also propagate the data to disk. */
231 if (db->persistent)
233 // XXX async OK?
234 uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
235 msync ((void *) pval,
236 ((uintptr_t) dataset & pagesize_m1)
237 + sizeof (struct dataset) + req->key_len, MS_ASYNC);
240 (void) cache_add (req->type, key_copy, req->key_len,
241 &dataset->head, true, db, uid, he == NULL);
243 pthread_rwlock_unlock (&db->lock);
245 /* Mark the old entry as obsolete. */
246 if (dh != NULL)
247 dh->usable = false;
251 else
254 written = total = (offsetof (struct dataset, strdata)
255 + start * sizeof (int32_t));
257 /* If we refill the cache, first assume the reconrd did not
258 change. Allocate memory on the cache since it is likely
259 discarded anyway. If it turns out to be necessary to have a
260 new record we can still allocate real memory. */
261 bool alloca_used = false;
262 dataset = NULL;
264 if (he == NULL)
265 dataset = (struct dataset *) mempool_alloc (db, total + req->key_len,
268 if (dataset == NULL)
270 /* We cannot permanently add the result in the moment. But
271 we can provide the result as is. Store the data in some
272 temporary memory. */
273 dataset = (struct dataset *) alloca (total + req->key_len);
275 /* We cannot add this record to the permanent database. */
276 alloca_used = true;
279 dataset->head.allocsize = total + req->key_len;
280 dataset->head.recsize = total - offsetof (struct dataset, resp);
281 dataset->head.notfound = false;
282 dataset->head.nreloads = he == NULL ? 0 : (dh->nreloads + 1);
283 dataset->head.usable = true;
285 /* Compute the timeout time. */
286 timeout = dataset->head.timeout = time (NULL) + db->postimeout;
288 dataset->resp.version = NSCD_VERSION;
289 dataset->resp.found = 1;
290 dataset->resp.ngrps = start;
292 char *cp = dataset->strdata;
294 /* Copy the GID values. If the size of the types match this is
295 very simple. */
296 if (sizeof (gid_t) == sizeof (int32_t))
297 cp = mempcpy (cp, groups, start * sizeof (gid_t));
298 else
300 gid_t *gcp = (gid_t *) cp;
302 for (int i = 0; i < start; ++i)
303 *gcp++ = groups[i];
305 cp = (char *) gcp;
308 /* Finally the user name. */
309 memcpy (cp, key, req->key_len);
311 assert (cp == dataset->strdata + total - offsetof (struct dataset,
312 strdata));
314 /* Now we can determine whether on refill we have to create a new
315 record or not. */
316 if (he != NULL)
318 assert (fd == -1);
320 if (total + req->key_len == dh->allocsize
321 && total - offsetof (struct dataset, resp) == dh->recsize
322 && memcmp (&dataset->resp, dh->data,
323 dh->allocsize - offsetof (struct dataset, resp)) == 0)
325 /* The data has not changed. We will just bump the
326 timeout value. Note that the new record has been
327 allocated on the stack and need not be freed. */
328 dh->timeout = dataset->head.timeout;
329 ++dh->nreloads;
331 else
333 /* We have to create a new record. Just allocate
334 appropriate memory and copy it. */
335 struct dataset *newp
336 = (struct dataset *) mempool_alloc (db, total + req->key_len,
338 if (newp != NULL)
340 /* Adjust pointer into the memory block. */
341 cp = (char *) newp + (cp - (char *) dataset);
343 dataset = memcpy (newp, dataset, total + req->key_len);
344 alloca_used = false;
347 /* Mark the old record as obsolete. */
348 dh->usable = false;
351 else
353 /* We write the dataset before inserting it to the database
354 since while inserting this thread might block and so would
355 unnecessarily let the receiver wait. */
356 assert (fd != -1);
358 #ifdef HAVE_SENDFILE
359 if (__builtin_expect (db->mmap_used, 1) && !alloca_used)
361 assert (db->wr_fd != -1);
362 assert ((char *) &dataset->resp > (char *) db->data);
363 assert ((char *) dataset - (char *) db->head
364 + total
365 <= (sizeof (struct database_pers_head)
366 + db->head->module * sizeof (ref_t)
367 + db->head->data_size));
368 written = sendfileall (fd, db->wr_fd,
369 (char *) &dataset->resp
370 - (char *) db->head, dataset->head.recsize);
371 # ifndef __ASSUME_SENDFILE
372 if (written == -1 && errno == ENOSYS)
373 goto use_write;
374 # endif
376 else
377 # ifndef __ASSUME_SENDFILE
378 use_write:
379 # endif
380 #endif
381 written = writeall (fd, &dataset->resp, dataset->head.recsize);
385 /* Add the record to the database. But only if it has not been
386 stored on the stack. */
387 if (! alloca_used)
389 /* If necessary, we also propagate the data to disk. */
390 if (db->persistent)
392 // XXX async OK?
393 uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
394 msync ((void *) pval,
395 ((uintptr_t) dataset & pagesize_m1) + total +
396 req->key_len, MS_ASYNC);
399 (void) cache_add (INITGROUPS, cp, req->key_len, &dataset->head, true,
400 db, uid, he == NULL);
402 pthread_rwlock_unlock (&db->lock);
406 free (groups);
408 if (__builtin_expect (written != total, 0) && debug_level > 0)
410 char buf[256];
411 dbg_log (_("short write in %s: %s"), __FUNCTION__,
412 strerror_r (errno, buf, sizeof (buf)));
415 return timeout;
419 void
420 addinitgroups (struct database_dyn *db, int fd, request_header *req, void *key,
421 uid_t uid)
423 addinitgroupsX (db, fd, req, key, uid, NULL, NULL);
427 time_t
428 readdinitgroups (struct database_dyn *db, struct hashentry *he,
429 struct datahead *dh)
431 request_header req =
433 .type = INITGROUPS,
434 .key_len = he->len
437 return addinitgroupsX (db, -1, &req, db->data + he->key, he->owner, he, dh);